The present invention relates to an attachment attached to an ultrasound probe for clinical application.
An ultrasound probe comprises a transducer array having a plurality of transducer elements aligned in a single direction. Ultrasound beams are radiated from the transducer elements toward a human body and are deflected therein in a predetermined direction, thereby scanning the human body. For example, in a sector scan method, the ultrasound beams are deflected in a fan shape, while in a linear scan method, the supersound beams are deflected in directions parallel to each other. Ultrasound beams reflected by the interior of the human body are received by the transducer elements. The received ultrasound beams are converted to eletrical signals. Then, a tomographic image of the human body is displayed on a cathode-ray tube in correspondence with the electrical signals. In order to sequentially diagnose tomographic images of the human body, an operator moves the ultrasound probe in a direction perpendicular to the deflecting direction of the ultrasound beams.
When an organ which is near the surface of the patient's skin is to be diagnosed, an attachment incorporating an acoustic medium is often attached to the ultrasound probe. FIGS. 1 to 3 show this attachment. Attachment 2 comprises resin casing 3 storing an acoustic medium, and attachment section 4 for attaching the casing 3 to probe 1. Contact membrane 5 formed of silicone rubber is provided to the distal end portion of casing 3.
As shown in FIGS. 1 and 2, casing 2 normally has a cubic shape. More specifically, surface 6, parallel to the deflecting direction of the ultrasound beams, has a rectangular shape, as shown in FIG. 1. Surface 7, perpendicular to the deflecting direction of the ultrasound beams, has also a rectangular shape. For this purpose, contact membrane 5 has relatively large width W. When the operator moves the ultrasound probe, frictional resistance between the skin surface and the contact membrane of the attachment is increased. For this reason, when the operator moves the probe along the skin surface, the attachment has poor operability. When the attachment is turned while being brought into contact with the skin surface, the attachment cannot be satisfactorily contact with the human body. Therefore, the contact between the membrane of the attachment and the skin surface is degraded.
As shown in FIGS. 1 to 3, the attachment has a flat contact membrane. For this reason, as indicated by the arrow in FIG. 3, the ultrasound beams are reflected by the inner surface of the contact membrane 5, are multiple-reflected by the inner surface of casing 3, and are then received by the transducer elements. In this case, a multiple-reflected image is displayed on the cathode-ray tube, thus hindering a precise diagnosis (reading). When the contact membrane is flat, if a neck (for example) is to be diagnosed, contact between the membrane and the skin surface is degraded.
The attachment may comprise a flexible water bag. In this case, when the water bag is brought into contact with the skin surface, since its contact membrane is flat, a multiple-reflected image is displayed on a cathode-ray tube, and a precise diagnosis (reading) cannot be performed.